Results for area 1.5 Communication protocols and networks
functional entity providing multiplexing and demultiplexing functionality for data and session control commands
roadside equipment that communicates with the roadside units such as signal controllers and the in-vehicle units using radio signals
internal architectural component of the SNMP architecture as defined in IETF RFC 3411
NOTE 1 to entry Defined SNMP applications include the command generator, command responder, notification
originator, notification receiver, and proxy forwarder.
top layer of the OSI seven-layer model as defined in ISO/IEC 7498-4
NOTE This layer defines the structure and format of the data packet content along with the rules and procedures for exchanging data packets.
network operating using an air-interface capable of bi-directional transfer of data and or voice
NOTE 1 to entry There are different types of wireless communications such as PAN, LAN, cellular network, etc.
wireless communications network consisting of multiple adjacent access points (cells) with the capability of homogeneous transfer of a communications session instance to an adjacent cell without significant interruption to the session
application layer and the communication profile for CAN-based networks
system or device to which the information in the data packet is intended to be sent
identifier of an application-entity to a transport service in the internet suite of protocols
NOTE The concept of port numbers is often present in OSI literature; however, port numbers are not inter-network standardized, but exist as local network conventions only.
entity of data containing enough information to be routed from source to destination without relying on previous network configuration
EXAMPLE IP datagram.
entity of data that can be sent between end-application systems in order to exchange information
NOTE A data packet relates to the Application Layer of the OSI stack and may be broken into several pieces by lower layer protocols.
active communication session created when the in-vehicle equipment at a time of its choosing initialises a time controlled session in order to send a message/exchange data, or it receives an inbound call the session is ended as soon as the task is achieved;
EXAMPLE Such as receipt of a safety message from the infrastructure.
bi-directional communication sequence between two parties in accordance with predetermined protocols
NOTE 1 to entry The term “dialog” represents the American English spelling.
NOTE 2 to entry The term “dialogue” can be used when the interface context is known.
long range communications interface
the downlink refers to that portion of a communications link used for the transmission of information from the infrastructure to each in-vehicle unit
traditional permanent ‘wired’ connection (although may in reality include microwave and other wireless connections)
specific combination of physical and data link layer protocols as defined in IEEE 802.3 that allow multiple systems to gain access to a shared medium and communicate with one another
data packet sent to indicate that the sending system is still alive and communicating
process by which a communication link is switched from one virtual communication interface to another one of a different medium type
process by which a communication link is switched from one virtual communication interface to another one of the same medium type
information that is exchanged between physical objects
an information telephone call, typically automated
really simple syndication comprises a Web feed format used to publish frequently updated sources of information
vehicle-to-vehicle and vehicle-to-roadside
wireless (and in some cases, wireline) networks that facilitate data exchange, including roadside ITS stations where appropriate
layered solution that enables continuous or quasi continuous communications between vehicles and the infrastructure, or between vehicles, using such (multiple) wireless telecommunications media that are available in any particular location, and which have the ability to migrate to a different available media where required and where media selection is at the discretion of user determined parameters by using a suite of standards based on ISO 21217 (CALM architecture) and ISO 21210 (CALM networking) that provide a common platform for a number of standardised media using ITS-stations to provide wireless support for applications, such that the application is independent of any particular wireless medium
short range communications interface
the conceptual layer of control or processing logic existing in the hierarchical structure of a station that is responsible for maintaining control of the data link
NOTE The data link layer functions provide an interface between the station higher layer logic and the data link. These functions include address/control field interpretation, channel access and command PDU (protocol data unit) /response PDU generation, transmission and interpretation.
any entity upon which a signal is impressed or from which a signal is received, e.g. wireless or on a wire, radio waves or light, low or high frequency band, modulation scheme
assembly of communication parameters of all protocol layers such that a consistent communication protocol is provided
mobile communication facility capable of receiving information from the fixed equipment on the downlink and, optionally, also capable of transmitting information to the fixed equipment on the uplink
NOTE The mobile equipment normally corresponds to the vehicle’s communication unit.
electromagnetic signal that can be modulated to carry lower frequency encoded information across an air interface
area of radio coverage consisting of one or more cells controlled by one RNC
NOTE 1 to entry The boundaries of a RNC area and a location area are independent; a location area may span the boundary between RNC area and a RNC area may span the boundary between location areas.
logical channel in a communications system
NOTE UDP and TCP use port numbers to multiplex data packets from a variety of applications onto a single communications system.
physical element of a node where a link is connected; nodes may have one or more ports;each
port may connect to one or more physical ports on (sub) nodes that are contained within the node
reference model developed by ISO to enable different or similar systems to dialogue with one another
NOTE 1 This model constitutes a reference framework for describing data exchanges. Each layer performs a service at the request of the adjacent higher layer, and in turn, requests more basic services from the lower layers. It is described in 7 layers.
NOTE 2 Open systems interconnection (OSI) is an international effort to facilitate communications among computers of different manufacture and technology.
connectionless protocol from the TCP/IP set , belonging to the transport layer; similar to TCP, it uses protocol IP, but does the delivery without confirmation
industrial Ethernet is the name given to the use of the Ethernet protocol in an industrial environment, for automation and machine control
set of services which are responsible for providing a virtually error-free, point-to-point connection so that host A can send data packets to host B and they will arrive uncorrupted
NOTE Connection-oriented transport profiles may also ensure that the data packets arrive in the correct order.
service that provides end-system to end-system communications without any connection set-up
EXAMPLE UDP/IP.
process of switching a communications transaction in progress from one communication cell to another or between radio channels in the same cell
NOTE Handover is used to allow established sessions to continue when mobile stations move from one cell/AP to another and as a method for minimizing co-channel interference.
electronic device that is connected using one or more communication media
beacon, antenna or similar source of signal propagation and receipt together with equipment to manage communication sessions with users operating within the operating reach of the network access point and provide connectivity for the users within the operating reach of the single access point to a wider communications network
NOTE 1 to entry A network access point may, but does not need to provide homogeneous or heterogeneous handover to another network access point.
interface point between data link layer and application layer that has a unique Link Identifier and that allows layers to communicate
DATEX-ASN publication (reply) that is sent directly over the given transport profile, in contrast with a file publication
DATEX-ASN publication (reply) that is stored on the server’s file system until the client has an opportunity to retrieve it via a file transfer protocol, in contrast with datagram publication
period of time during which a client and a server exchange multiple data packets
layer that manages the dialogue between end-user application processes including restart, termination, and checkpointing
NOTE The session layer constitutes layer 5 of the OSI model.
set of routines, protocols, and tools for building software applications
[SOURCE: ISO 17627:2009, 2.4, modified]
NOTE 1 to entry An API expresses a software component in terms of its operations, inputs, outputs, and underlying types; it defines functionalities that are independent of their respective implementations, which
allows definitions and implementations to vary without compromising the interface. An API can also assist otherwise distinct applications with sharing data, which can help to integrate and enhance the functionalities of
the applications.
NOTE 2 to entry APIs often come in the form of a library that includes specifications for routines, data structures,
object classes, and variables. In addition to accessing databases or computer hardware, such as hard disk drives or video cards, an API can be used to ease the work of programming graphical user interface components.
refers to the use of a neighbouring DSRC channel by two or more emissions
communication bus with measured inputs and controlled outputs
network designed for use in automotives, which:
a) uses a single terminated twisted pair cable;
b) is multi master;
c) uses a maximum signal frequency used is 1 Mbit/sec;
d) has a typical length of 40 M at 1 Mbit/sec up to 10 KM at 5 Kbits/sec;
e) has high reliability with extensive error checking;
f) has a typical maximum achieveable data rate of 40 KBytes/sec;
g) has a maximum latency of high priority message <120 μsec at 1 Mbit/sec
NOTE 1 to entry CAN is unusual in that the entities on the network, called nodes, are not given specific addresses.
Instead, it is the messages themselves that have an identifier which also determines the messages’ priority. For this reason, there is no theoretical limit to the number of nodes, although in practice it is ~64.
layer that provides functional and procedural means of transferring variable length data sequences from a source to a destination
NOTE The network layer constitutes layer 3 of the OSI model.
the Short Data Service is designed to send relatively short messages (up to 2047 bits) or predefined status messages and is implemented as part of signalling of the system TETRA
functional entity responsible for establishing secure communications sessions with its peer instances
data structure broadcast from the RSU to the OBUs
refers to the use of a neighbouring DSRC channel by two or more emissions
NOTE It is possible that a DSRC channel has either one or two adjacent channels.
locus of relations among nodes
NOTE 1 to entry It provides interconnections between nodes for communication and coordination; may be
implemented by a wired connection or with some radio frequency (RF) or optical communications media; links
implement the primary function of transporting data; links connect to nodes at a port.
a specialist Professional Mobile Radio and two-way transceiver
NOTE 1 to entry Formerly known as Trans European Trunked RAdio.
NOTE 2 to entry It uses Time Division Multiple Access (TDMA) with four user channels on one radio carrier and 25 kHz spacing between carriers. Both point-to-point and point-tomultipoint transfer can be used. Digital data transmission is also included in the standard though at a low data rate.
the name of a fully digital radio communication standard for professional communications organisations; it is based on an FDMA (frequency division multiple access) multiplex approach using a narrowband channel operating at 12,5 kHz channel spacing
to ignore a data packet
NOTE A data packet that is silently dropped does not cause any action to occur within the receiving system, nor is any response sent to the subject data packet.
the uplink refers to that portion of a communications link used for the transmission of information from each in-vehicle unit to the infrastructure
mobile wireless communications network with access to a public telecommunications network
the CAN data link layer protocol for serial communication as specified in ISO 11898-1; the CAN Open is a CAN-based higher layer protocol; it was developed as a standardised embedded network with highly flexible configuration capabilities
protocol for transmitting private information via the Internet by using public and private keys to encrypt data
layer that sits on top of the communication stack and helps to provide data interoperability and reuse, and to manage applications and enable dynamic real time loading of new applications
elementary communication service provided by the application layer protocol to the application processes
NOTE 1 to entry The invocation of a service primitive by an application process implicitly calls upon and uses services offered by the lower protocol layers.
see mobile wireless communications network device
area of radio coverage consisting of one or more cells controlled by one BSC
NOTE 1 to entry The boundaries of a BSC area and a location area are independent; a location area may span the boundary between BSC area and a BSC area may span the boundary between location areas.